After playing the beta I just lost all interest. It wasn't even the bugs and lag that got to me, because I am aware that those are always issues that are going to come up in a beta. It is the game itself. I did not feel fear.
Playing Diablo I and II, I would travel into the deepest dungeons and caves, slowly making my way through the almost pitch black darkness, when suddenly out of nowhere I would be swamped by a horde of skeletons and imps trying to tear the flesh from my bones. I would fight for survival, barely making my way through and crawling to safety with the help of my last town portal scroll. In D3, I could waltz into a basement or a cave and immediately see where all the enemies were and the art style did nothing to help. They have WoW'd the graphics and I no longer find the monsters scary.
In the previous games, the enemy animations and art gave me chills. I remember the little shamans that move lightning fast, jumping all over the place. The vultures swamping me throughout the desert with their weird heads. Something about the stuttering, staccato movements and attacks were what enthralled me. D3 doesn't have that feel. It's like WoW, just from a top-down isometric-style and without dwarves. That doesn't really appeal to me.
Perhaps it's just me, but the DRM and RMAH are just two things that don't draw me to the game, the real problem is that it no longer feels like Diablo to me.